From this budget,we can invest an additional 20k in infrastructure bonds.Had a couple of question on this .

What are infrastructure bonds.?Is it a good option if we have already invested 1 lac in PPF+Term insurance+MF.?Let me know which infrastructure bond to invest in?How can i buy them.?Are there any risk in that.?

I would not look at an INFRA Bond even though it saves an additional 20K on tax but investors should also know that money is locked in for 10 years. Would I want to lock in my money for tax benefits for 10 years when I know same amount invested in MF/stocks would give me higher returns.

Infrastructure bonds are issued basically by the Government for the infrasturcture/devlopment of country.
Yes its a good option, we can save additional tax.
You can invest in any of the companies – IDFC, IFCI have already started, LIC will follow soon.
You need to have a Demat account to buy them.
There are no risks involved but the returns would be around 7-8% which will just manage to beat inflation.
I am going to invest in these bonds.